<%@ Title="Basic TRequiredFieldValidator" %> <com:TContent ID="Content"> <h1>Basic TRequiredFieldValidator Test1</h1> <com:TTextBox ID="text1" /> <com:TRequiredFieldValidator ID="validator1" FocusOnError="true" FocusElementID="<%# $this->Page->text2->ClientID %>" ControlToValidate="text1" ErrorMessage="*" /> <com:TButton ID="button1" Text="Click" /> <com:TTextBox ID="text2" /> </com:TContent>